Method of coating cans and attaching end members thereto



H. ONEIL Sept. 10, 1940.

METHOD OF COATING CANS AND ATTACHING END MEMBERS THERETO Filed 1, 1937Patented Sept. 10, 1940 v UNITED STATES PATENT OFFICE' METHOD OF COATINGCANS AND ATTAOH- ING END MEMBERS THERETO J amcs H. ONeil, Syracuse, N.Y., assignor to Continental Can Company, Inc., New York, N. Y., acorporation of New York Application November- 1, 1937, Serial No.172,302 2 Claims. (01. 113-120) The invention relates generally to theart of the description, the appended claims, and the sevforming metallicreceptacles and has for an' oberal views illustrated in the accompanyingdrawject to provide a novel method of coating cans ing. and attachingend members thereto in a manner In the drawing:

for assuring against the presentation, of bare Fig. 1 is a detailvertical section illustrating the 5 metal portions to contact withcontained prodstep of coating the can.

ucts- Fig. 2 is a detail vertical section illustrating It is customaryto interiorly coat metallic conthe step of air dryingthe can. tainersadapted to receive certain products, so Fig. 3 is an enlargedfragmentary section illusthat direct contact between said products andtrating the step of seaming an end member in m the metal of thecontainers is avoided. This'is place while the protective coating is ina tacky particularly true in the canning of beer, since it state.

has been found that the slightest exposure of the Fig. 4 is afragmentary diagrammatic section tin forming the outer surface of themetal causes illustrating the step of baking the end member a chemicalreaction upon the beer sufficient to equipped can to harden theprotective coating change its appearance, making it cloudy and unanddrive out volatile solvents confined within 15 marketable. Theprotective coating has been apthe end member securing seam.

plied in various ways, as by dipping, flushing, or In practicing themethod, the can bodies 5 are flooding the inside, outside, or bothinside and coated interiorly, or both interiorly and exterior-1y,outside'of the can bodies in the coating solution, by any approvedmethod. As a single exemplifiusually lacquer or enamel. An example ofapcation of the coating step I have shown, in Fig. 1 paratus capable ofcoating can bodies by the dipof the drawing, a portion of the Kronquestpatent ,ping method is to be found in the application for applicationapparatus hereinbefore referred to. Letters Patent filed by Alfred L.Kronquest, on The can bodies are supported on individual car- April 12,1937, Serial Number 136,473 now-Patent riers 6 which are lowered andlifted by suitable Number 2,206,778. After the protective coatingsmechanisms to immerse the cans in and remove are applied they aresuitablyhardened, as by them from the protective coating bath 1. Afterbakingthe cans are coated internally and externally by Hardened coatingsof the character stated are this immersion they a attached t0 clips 3somewhat brittle, and when can ends are applied, pending from a conveyorchain 9 and are carried and seamed securely in place, usually by adouble along in an air drying chamber. 30 roll seam, portions of thehard. coatings are This air drying step is il s in 2 cracked or rupturedby the rolling of the scam, the drawi g a may be carried on with orWithand as a result, bare metal surfaces are exposed 'out forcedcirculation and in the presence of to contact with products to becontained in the heat or without it asmaybe desired, the demands 3 cans.v of the invention being satisfied by any form of Seeking to remedythese faults, the invention drying which will suitably bring the cancoatings resides in the novel method of coating cans and to a tackystate. attaching end members thereto, which comprises After the coatingand the air drying steps the steps of interiorly coating the can bodies,air have been completed an end member ID is im--' 40 drying the coatingsto a tacky state, applying end mediately applied to the can' body andseamedmembers, seam-securing said members in place securely in place asindicated at H in Fig. 3 of while the coatings are tacky and includingtacky the drawing. While the invention is not limited coated portions inthe seams, then baking the to the formation of a double roll seam thisform N member equipped cans to harden said coatings of scam is commonlyemployed for this purpose 45 and drive .out volatile solvents containedin said and is for that reason illustrated herein'as an seams.exemplification of the step of seam-securing an With the above and otherobjects in view that end member on a tacky, coated can. Any of the willhereinafter appear, the nature of the invenwell known double seamingmechanisms may be tion will be more clearly understood by followingemployed in performing this step of the method 50' and an example ofsuch mechanisms is to be found in the patent to A. L. Kronquest, issuedApril 1,1930, as No. 1,752,912. In these mechanisms the double seam isformed by a chuck and successively operable first and second operationand chipping or flaking off and exposing the bare metal is avoided. Theplasticity of the coating also aids somewhat in the formation of aperfect seal in the-seam because of its ability to conform readily tothe interstices between the seam components.

1 The end members referred to herein are, of course, the can bottomclosures, the top end closures being attached after the cans have beenfilled at the brewery. During the draining off of the surplus protectivecoating material, as shown inFig. 2, the can body end to which thebottom closure is to be applied is held uppermost. Due to the action ofgravity, and the surface tension of the draining coating material, theapplied coating film at the extreme upper end of the can body thins outto a considerable extent and, if allowed to harden, would become brittleand. inadequate as hereinbefore stated. The herein described method ofattaching the bottom closures to the can body ends while the coatingsare tacky overcomes the difiiculties referred to. No such problems arepresented at the lowermost or can top closure receiving ends because thecoating material drains of! in the direction of these ends, as shown inFig. 2, and an adequate protective coating always is provided at saidends.

What I claim is: y

1. The method consisting in coating the entire interior surface of a canbody with a fluid coating, draining the superfluous fluid coating fromthe body while one coated end of the latter is uppermost, drying theremaining fluid coating to a tacky condition while said end isuppermost, and seam-securing a closure member coated on its interiorface to said end of the body while the tacky condition of the can bodycoating persists, including the rolling into the seam of part-of saidtackily coated end, and thereafter hardening the coating.

2. The method consisting in immersing a can body in a fluid coating,draining the superfluous fluid coating from the body while one end ofthe latter is uppermost, drying the remaining fluid coating to a tackycondition while said end -is uppermost, double seam-securing a closuremember coated on its interior face to said end of the body whfle thetacky condition of the can body coating persists, including the rollinginto the seam of part of said. tackily coated end, and. thereafterbaking the coating.

JAMES H. ONEIL.

